Nowadays, high speed data transmission in wireless communication system becomes more and more important. This trend raises a very high requirement of data processing capability in wireless communication system. Multiple-input Multiple-output (abbr. MIMO) communication system is rising, using several distributed processing devices which contain several digital signal processors (DSP) to process physical layer data in parallel, in MIMO system.
Due to the characteristic of multi-antenna MIMO system, operations such channel estimation for multiple channels, modulating and demodulating for data sent and received by multiple antennas need to be done by every processors synchronously. For example, received data from multi-antenna are needed to be processed synchronously: each processor processes one antenna's received data separately, and every processor process the physical layer data of the same frame and send the data to MIMO demodulator at the same time. Thus, synchronous operation among the several processors turn into extremely necessary.
Currently, synchronization among several processors in multi-antenna MIMO system is realized by means of software. For example, each processor is controlled by its respective controlling process, and every controlling process realizes their synchronization through inter-process communication such as signal value or signal light, semaphore, or shared global variant, and indirectly controls each processor to operate synchronously. In addition, in some current technical solutions, each process is running on a different CPU, and each CPU is connected by Ethernet network. In this case, each process is also synchronized through the Ethernet protocol.
Since the communication speed of multi-antenna MIMO is very high, accordingly, the requirement of synchronization processing speed is also high, thus time overhead for synchronization should be as small as possible, and this often requires real-time synchronization. In the current art, implementing synchronization among distributed modules by means of software, such as inter-process communication, generally has larger latency, especially in the case of there is a large number of processes that need to be synchronized. The synchronization latency is usually as long as several milliseconds to tens of milliseconds, thus it will be difficult to meet the real-time synchronization requirement of the multi-antenna MIMO system.